Preserve Unicode strftime output in non-UTF-8 locales by youknowdot · Pull Request #9050 · RustPython/RustPython

youknowdot · 2026-10-10T10:02:01Z

Summary

Extract the independent Linux/macOS strftime locale-output fix from #8954 (43065e79ddc46eafeca58cb39398ac007b5d25f7) onto Python 3.14 main (3af5f8a15314446d2b28a90e429c938dc7b8beeb).

Use wcsftime on Linux and macOS rather than interpreting narrow libc output as UTF-8. This preserves localized month/day text when the selected locale uses another encoding. Windows is unchanged, and other Unix targets retain the existing narrow fallback, including OpenBSD.

The production hunks are taken directly from the pinned mega PR and match CPython 3.14.7's wide-formatting path. No Python 3.15 behavior or unrelated migration changes are included. Searches found no dedicated duplicate; merged #7090 is Windows-specific, and #7671 covers earlier Unicode literal passthrough.

Add bounded coverage to the existing time snippet for localized output, Unicode/surrogate/NUL composition, and buffer growth. Save/set/restore LC_ALL, since macOS's libc conversion also depends on LC_CTYPE. Locales remain optional for hosts where they are not installed; the local verification explicitly exercised both rather than silently skipping them.

Validation

Exact CPython 3.14.7: complete updated snippet passes; both French ISO-8859-1 and UTF-8 locale paths executed.
Unchanged native main fails the new localized-month assertion; this head passes the full snippet and its pytest entry.
Native proof explicitly verifies both LC_TIME and LC_CTYPE are set to each requested locale and produces the correct Unicode month in both encodings.
All 5 existing canonical TimeTestCase strftime tests pass, including Unicode/surrogate/NUL and format/bounds checks.
Host-environment Clippy and separate C-API Clippy with warnings denied; normal repository commit hooks.
Independent source review checked the FFI signature, platform wchar_t layout, initialized buffers, lengths, lifetimes and growth, and caught/corrected the macOS locale-category test assumption.

No canonical assertions, implementation-name guards, or README text were changed; no Rust behavioral tests were added. Native validation is Linux-only, not a complete workspace or macOS execution claim. Full hosted CI is pending; this remains a draft for review.

AI-assisted implementation and validation with OpenAI Codex; model identifier unavailable. No human review is implied.

Summary by CodeRabbit

Bug Fixes
- Date and time formatting on Linux and macOS now better supports Unicode, including non-English month names and emoji in format strings.
- Invalid characters in formatted output are replaced safely, and longer formatted results are supported.
- Embedded NUL characters in format strings are rejected. Other Unix platforms retain their existing formatting behavior.

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coderabbitai · 2026-10-10T10:02:09Z

No actionable comments were generated in the recent review. 🎉

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📒 Files selected for processing (2)

crates/host_env/src/time.rs
extra_tests/snippets/stdlib_time.py

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📝 Walkthrough

Walkthrough

Linux and macOS now use wcsftime for strftime formatting. The implementation handles embedded NUL formats, grows the output buffer, and replaces values that cannot be represented as Unicode. Tests cover available French locales.

Changes

Unicode strftime

Layer / File(s)	Summary
Wide-character formatting and validation `crates/host_env/src/time.rs`, `extra_tests/snippets/stdlib_time.py`	Linux and macOS use `wcsftime`; other Unix targets retain narrow `strftime`. Tests check formatting with available French locales, including Unicode and special characters.

Priority: ➖ Normal

Estimated code review effort: 2 (Simple) | ~10 minutes

Change: Bug fix

Suggested reviewers: youknowone

Merge Risk: ⚪ Minimal · up to fd23f

This change preserves localized Unicode strftime output on Linux and macOS. No actionable merge-blocking risk was identified; hosted CI and macOS validation remain pending.

Pre-merge checks | 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Description Check		Check skipped - CodeRabbit’s high-level summary is enabled.
Title check		The title clearly and concisely describes the main change: preserving Unicode output from strftime in non-UTF-8 locales.
Docstring Coverage		Docstring coverage is 100.00% which is sufficient. The required threshold is 80.00%. Docstring coverage is scoped to functions touched by this diff. Analyzed 3 functions across 2 files.
Linked Issues check		Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check		Check skipped because no linked issues were found for this pull request.

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chatgpt-codex-connector · 2026-10-10T10:58:14Z

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📝 Code Review	✅ Completed 2026-10-10T11:04:19.851627Z	`fd23fb6`	Draft marked ready

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chatgpt-codex-connector · 2026-10-10T11:04:17Z

 }

-#[cfg(windows)]
+// These Unix platforms provide wcsftime, which returns locale text as Unicode.


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This commit states that it was AI-assisted, but its message ends with prose rather than the mandatory Assisted-by: AGENT_NAME:MODEL_VERSION trailer, so it does not meet the repository's critical disclosure policy; add the prescribed trailer before landing.

AGENTS.md reference: AGENTS.md:L20-L23

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chatgpt-codex-connector · 2026-10-10T11:04:17Z

+            except locale.Error:
+                continue
+            february = (2024, 2, 1, 12, 0, 0, 3, 32, 0)
+            assert time.strftime("%B", february) == "février"


Remove the prohibited test logic

The newly added locale block changes test data, control flow, and assertions in an existing snippet test, but the repository's critical test-file policy permits only expected-failure decorator and associated TODO edits. Drop this regression block rather than modifying stdlib_time.py as part of the fix.

AGENTS.md reference: AGENTS.md:L273-L279

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Decode strftime locale output through wide characters

fd23fb6

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youknowone approved these changes Oct 10, 2026

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youknowone marked this pull request as ready for review October 10, 2026 10:58

youknowone enabled auto-merge (squash) October 10, 2026 10:58

chatgpt-codex-connector Bot reviewed Oct 10, 2026

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youknowone merged commit eb162b4 into RustPython:main Oct 10, 2026
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Preserve Unicode strftime output in non-UTF-8 locales - #9050

Preserve Unicode strftime output in non-UTF-8 locales#9050
youknowone merged 1 commit into
RustPython:mainfrom
youknowdot:fix-strftime-locale-unicode

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